1. Field of the Invention
The present invention relates generally to hose couplings and, more particularly, to plastic couplings for the ends of flexible, resilient hoses of the so-called garden hose type.
2. Description of the Prior Art
Garden hoses made of various forms of rubber and plastic compositions are typically provided with so-called male and female end couplings by which the hoses may be readily connected to one another, to faucets or spigots supplying liquid thereto, and to nozzles, sprinklers and the like for dispensing the liquid.
On currently marketed hoses such couplings, which are permanently affixed to the hose ends during production of the hose assembly, are generally of two types. In one, threaded male and female couplers of plastic or brass have a barbed stem which is inserted into the hose end. A clamp member, generally of brass, surrounds the external periphery of the hose and urges it into liquid-tight engagement with the stem. In the other, the threaded male and female couplers, generally of brass or the like, include a tubular sleeve which fits over the outer end of the hose. A ferrule, again of brass or the like, is inserted into the hose end and permanently expanded outwardly to urge the hose into liquid-tight engagement with the tubular sleeve.
The hoses tend to bend most sharply immediately adjacent the coupling during normal use and, after repeated flexing, tend to develop cracks around the coupling until they eventually leak and even break completely off of that point. The metallic components are fabricated of relatively thin sections so that they are easily bent out of shape and permanently deformed by being stepped upon or run over by vehicles. As a result, it may be impossible to couple the hose to an appropriate associated male or female coupling unit or, if it can be so coupled, the joint connection may leak.
Metallic couplings of the aforedescribed types are relatively costly to fabricate and assemble. Both the material itself and the forming process are comparatively expensive. The female units comprise two separate pieces which must be assembled before the coupling is affixed to the hose, thereby complicating the assembly process.
It has been found that the hoses themselves tend to have a longer service life than the prior art original couplings. As a result, replacement couplings have been developed which can be applied to a hose end by the use in place of the original factory applied coupling. One such unit comprises a barbed stem for insertion into the hose, with an external clamp, such as a conventional screw clamp, for securing the hose around the stem. Another, as disclosed in U.S. Pat. No. 4,313,628, typically includes an external sleeve adapted to fit over the end of the hose, with a tapered bushing which threads into the hose and spreads or flares it outwardly against the sleeve. Such replacement couplings have not proven entirely satisfactory in that in either type, due to insertion of a member inside the hose, the diameter is effectively reduced and liquid flow is constricted. The external clamp or tapered internal bushing tends to loosen and allow the coupling to leak and eventually to pull apart. With the tapered insert, the stress is concentrated at the widest portion of the insert during assembly and thereafter, creating an area of likely hose fail.
In another improved hose coupling in U.S. Pat. No. 4,893,848, there is provided a coupling assembly for hoses, fabricated of plastic and comprising basic one-piece male and two-piece female coupling sections. The male section comprises an externally threaded fitting of standard dimensions and an integral coaxial hub adapted to slip over the end of the hose. The hub is provided with internal circumferential barbs of generally sawtooth configuration. The unit may be affixed to the hose end by inserting an expandable ferrule into the end of the hose and permanently deforming the ferrule to expand the hose material into engagement with the barbed interior surface of the hub. Alternatively, a plastic ferrule having external barbs similar to but oppositely directed from those of the hub, may be pressed into the end of the hose to expand it into engagement with the interior surface of the hub.
The female coupling section may comprise a two-piece snap-together unit including an annular collar adapted to slip over the end of the hose and having internal circumferential barbs similar to these of the male section. The annular collar is affixed to the hose end by means similar to those employed with the male section. An annular flange is formed on the collar, and an internally threaded connector is provided for coupling the collar to the male section. The connector has an inwardly turned annular lip adapted to snap over and engage behind the flange on the collar. The barbs are specially configured to bite into the hose material and resist separation of the coupling section from the hose in response to axial forces tending to pull them apart.
In certain instances it has been discovered that the liquid being handled by the hose coupling tends to leak between the internal threads of the annular collar of the female coupling section and the cooperating external threads of the male coupling section.